Construction Stage Seismic Vulnerability Evaluation of a Continuous Girder Bridge with the Cast-in-Place Cantilever Construction Method

Table 2

The modal information of the FEM.

Construction stage	Modal no.	Frequency (Hz)	Mode shape	Mode shape description
Substructure	1	21.236		Middle pier longitudinal bends
	2	34.176		Middle pier transversal bends
	3	81.022		Middle pier longitudinal bends
Middle cantilever	1	2.378		Middle pier longitudinal bends; main girder rotates around the supporter transversal direction
	2	3.539		Main girder rotates around the supporter vertical direction
	3	5.932		Middle pier transversal bends; main girder transversal bends
Long cantilever	1	1.161		Pier longitudinal bends; main girder rotates around the supporter transversal direction
	2	1.458		Main girder rotates around the supporter vertical direction
	3	2.570		Main girder vertical bends
Middle span closure/bridge completion	1	1.359		Main girder vertical bends
	2	2.421		One middle pier transversal bends; main girder vertical bends
	3	3.128		Middle piers transversal bends; main girder transversal bends